A G& CONTINUED: CLASSIFICATION. 



I6 9 



The fruiting portions are somewhat thickened as shown in the figure. 

 Within these portions are numerous oval cavities opening by a circular pore, 

 which gives a punctate appearance to these fruiting cushions. Tufts of hairs 

 frequently project through them. 



365. Structure of the concept acles. On making sections of the fruiting 

 portions one finds the walls of the cavities covered with outgrowths. Some 

 of these are short branches which bear a large rounded terminal sac, the 



Fig. 177. 



Oogonium of Fucus 

 with ripe eggs. 



Fig. 1 7S . 



Portion of plant of Fucus show- 

 ing conceptacles in enlarged ends; 

 and below the vesicles (Fucus 

 vesiculosus). 



Fig. 176. 



Section of conceptacle of Fucus, showing 

 oogonia. and tufts of antheridia. 



oogonium, at maturity containing eight egg cells. More slender and much- 

 branched threads bear narrowly oval antheridia. In these are developed 

 several two-ciliated spermatozoids. 



366. Fertilization. At maturity the spermatozoids and egg cells float out- 

 side of the oval cavities, where fertilization takes place. The spermatozoid 



